The present invention relates to a technique of collating image data, and more particularly to a technique of collating images, which is suitable for certifying the person himself and which collation is performed using finger print image data.
This application is based on Japanese Patent Applications No. 10-372205, filed Dec. 28, 1998 and No. 11-166768, filed Jun. 14, 1999, the entire contents of which are incorporated herein by reference.
Conventionally, in order to prevent illegal access to be had to secret information, the collation of the person himself is carried out through the input of a password, fingerprint, etc. Regarding a password, there is the likelihood of its being used by another""s stealth, whereas a fingerprint is the characterizing feature of the body and so it is less likely that it is used by another""s stealth. In view of this, the collation made by fingerprint has been being expected to have a high level of safety.
Conventional collation of the fingerprint was carried out in accordance with the following procedures. (1) obtain a fingerprint to be collated by an image reader as multi-gradation image data. (2) binarize the multi-gradation image data. (3) extract the characterizing points such as diverging points or ending points of the wrinkles constituting the fingerprint, from the binarized data. These characterizing points are called xe2x80x9ccharacterizing figuresxe2x80x9d or xe2x80x9cmaneushaxe2x80x9d. (4) compare the positional relationship between the characterizing figures that have been extracted and the characterizing figures of the person""s own fingerprint registered beforehand, and thereby determine the identicalness between the both.
However, in a case where the valley of the wrinkles of the subject""s finger-skin is shallow, or where the skin is too soft, when at the time of input the subject applies his finger onto the glass surface of the image reader, it happens that the wrinkles are crushed. As a result, there is the possibility that unclear images will only be obtained and so the subject will not be able to be authenticated. Although the proportion of the persons having such finger-skin wrinkles is on the order of several percentages, this value is the one that is as great as the values that cannot be ignored when considering the actual circumstances that 0.1% is required as the percentage of a failure to collate a fingerprint such as rejecting the right person, erroneously admitting another as being the right person, etc.
Also, it happens that the person has his finger injured or cut. Even when the finger has been slightly injured, in a case where the place is near the characterizing features, it results that the person himself can not be recognized as being the right person.
In the above-described conventional fingerprint collation method, unless the fingerprint image data that is input has its fingerprint clearly imaged out, this data couldn""t be accurately collated with the finger""s original.
Accordingly, it is an object of the present invention to provide an apparatus for and a method of collating image data, which make it possible to perform fingerprint collation, etc. without being affected by the characteristic of the finger skin, the presence of injuries, etc.
According to the present invention, there is provided an image collation apparatus for calculating identicalness between first image that is registered beforehand and second image that is input at a time of collation, comprising:
a define section which defines a plurality of regions in the first image;
a search section which searches out from the second image a region having a maximum correlation with each of the plurality of regions defined by the define section, as a maximum correlation region; and
a calculate section which calculates the identicalness between the first image and the second image according to a difference between a positional relationship of each of the plurality of regions defined by the define section and a positional relationship of the maximum correlation region.
According to the present invention, there is provided a computer readable recording medium storing a computer program which calculates identicalness between first image that is registered beforehand and second image that is input at a time of collation, the computer program comprising:
a define program which defines a plurality of regions in the first image;
a search program which searches out from the second image a region having a maximum correlation with each of the plurality of regions defined by the define program, as a maximum correlation region; and
a calculation program which calculates the identicalness between the first image and the second image according to a difference between a positional relationship of each of the plurality of regions defined by the define program and a positional relationship of the maximum correlation region.
According to the present invention, there is provided an image collation method of calculating identicalness between first image that is registered beforehand and second image that is input at a time of collation, comprising:
a definition step which defines a plurality of regions in the first image;
a search step which searches out from the second image a region having a maximum correlation with each of the plurality of regions defined by the definition step, as a maximum correlation region; and
a calculation step which calculates the identicalness between the first image and the second image according to a difference between a positional relationship of each of the plurality of regions defined by the definition step and a positional relationship of the maximum correlation region.
Additional objects and advantages of the present invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the present invention.
The objects and advantages of the present invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.